The invention relates to an air-compressing self igniting internal combustion engine, with a main combustion space and an insert adjoining the latter, accommodated in the cylinder head and having an antechamber which comprises a sphere-like combustion space and a conduit.
An insert provided for air-compressing internal combustion engines and featuring an antechamber and oblique injection is disclosed in "Technischer Rundschau", 25/90 page 37. In that device, the insert has, in the combustion space, in the region of the mouth of the conduit, an insertion pin with a spherical impact head, the underside of which is set obliquely to produce a moderate air turbulence. The glow plug protruding into the combustion space of the antechamber is arranged in the downward current, that is, downstream of the injection nozzle. Approximately half of the injection spray strikes the upper side of the impact head.
A high standard has already been achieved with such measures on the insert as regards fuel consumption, exhaust-gas and noise behavior.
It is the underlying object of the invention to reduce further the pollutant content in the exhaust gas by special measures on the antechamber side.
This and other objects and advantages are achieved according to the invention by the eccentricity of the conduit relative to the sphere-like combustion space and the special arrangement of the insertion pin with a pronounced positional offset relative to the conduit, which results in a substantially larger main inflow cross-section and a correspondingly smaller inflow cross-section of the air, and thus in more intensive mixing of the air with the fuel. This arrangement also reduces considerably the content of carbon monoxides and hydrocarbons and of particles in the engine exhaust gas, and meets all engine-specific requirements, e.g. with respect to naturally aspirated or supercharged engines and large- and small-volume engines.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.